Organic Chemistry I Mohammad Jafarzadeh Faculty of Chemistry, Razi University Organic Chemistry, Structure and Function (7th edition) By P. Vollhardt and N. Schore, Elsevier, 2014 1 2-4 Functional Groups: Centers of Reactivity CHAPTER 2 69 by an acid dissociation constant Ka. Removal of a proton from an acid generates its conju- gate base; attachment of a proton to a base forms its conjugate acid. Lewis bases donate an electron pair to form a covalent bond with Lewis acids, a process depicted by a curved arrow pointing from the lone pair of the base toward the acid. Electrophiles and nucleo- philes are species in organic chemistry that interact very much like acids and bases. The carbon–halogen bond in the haloalkane is its functional group. It contains an electrophilic carbon atom, which reacts with nucleophiles in a process called nucleophilic substitution. 2-4 FUNCTIONAL GROUPS: CENTERS OF REACTIVITY Many organic molecules consist predominantly of a backbone of carbons linked by single bonds, Manywith only organichydrogen moleculesatoms consistattached predominantly. They ofmay a backbonealso contain of carbonsdoubly linkedor triplyby singlebonded carbons,bonds,as well withas onlyother hydrogenelements atoms. attached. However, they may also contain doubly or R Function triply bonded carbons, as well as other elements. These atoms or groups of atoms tend to These atomsbe sitesor of groupscomparativelyof atoms high tendchemicalto be reactivitysites of andcomparatively are referred to highas functionalchemical groupsreactivity and areorreferred functionalities.to as functional Such groupsgroups have characteristicor functionalities properties,. and they control the reactiv- Carbon frame Functional ity of the molecule as a whole. provides group imparts Such groups have characteristic properties, and they control the reactivity of the molecule structure reactivity as a wholeHydrocarbons. are molecules that contain only hydrogen and carbon Hydrocarbons are molecules that contain only hydrogen and carbon We begin our study with hydrocarbons, which have the general empirical formula CxHy. Those containing only single bonds, such as methane, ethane, and propane, are called The generalalkanes.empirical Moleculesformula such asC cyclohexane,xHy, containing whoseonly carbonssingle formbonds a ring,are are calledcalled cycloalkanes.. Alkanes lack functional groups; as a result, they are relatively nonpolar and unreactive. The They arepropertiesrelatively andnonpolar chemistry andof theunreactive alkanes are. described in this chapter and in Chapters 3 and 4. Cycloalkanes Alkanes H2 CH4 CH3OOCH3 CH3 CH2OCH3 CH3OCH2OCH2OCH3 C Methane Ethane Propane Butane 2 H2C CH2 Double and triple bonds are the functional groups of alkenes and alkynes, respectively. H2C CH2 Their properties and chemistry are the topics of Chapters 11 through 13. Cyclopentane Alkenes and Alkynes H2 H C i CH2PCH2 CPCH2 HCq CH CH3OCqCH H2C CH2 f CH 3 H2C CH2 Ethene Propene Ethyne Propyne C (Ethylene) (Acetylene) H2 Cyclohexane A special hydrocarbon is benzene, C6H6, in which three double bonds are incorporated into a six-membered ring. Benzene and its derivatives are traditionally called aromatic, because some substituted benzenes do have a strong fragrance. Aromatic compounds, also called arenes, are discussed in Chapters 15, 16, 22, and 25. Aromatic Compounds (Arenes) H CH3 HHC HHC C C C C C C C C H C H H C H H H Benzene Methylbenzene (Toluene) 2-4 Functional Groups: Centers of Reactivity CHAPTER 2 69 by an acid dissociation constant Ka. Removal of a proton from an acid generates its conju- gate base; attachment of a proton to a base forms its conjugate acid. Lewis bases donate 2-4 Functional Groups: Centers of Reactivity CHAPTER 2 69 an electron pair to form a covalent bond with Lewis acids, a process depicted by a curved arrow pointing from the lone pair of the base toward the acid. Electrophiles and nucleo- philes are species in organic chemistry that interact very much like acids and bases. The by an acid dissociation constant Ka. Removal of a proton from an acid generates its conju- carbon–halogen bond in the haloalkane is its functional group. It contains an electrophilicgate base; attachment of a proton to a base forms its conjugate acid. Lewis bases donate carbon atom, which reacts with nucleophiles in a process called nucleophilic substitution.an electron pair to form a covalent bond with Lewis acids, a process depicted by a curved arrow pointing from the lone pair of the base toward the acid. Electrophiles and nucleo- philes are species in organic chemistry that interact very much like acids and bases. The carbon–halogen bond in the haloalkane is its functional group. It contains an electrophilic 2-4 FUNCTIONAL GROUPS: CENTERS OF REACTIVITY carbon atom, which reacts with nucleophiles in a process called nucleophilic substitution. Many organic molecules consist predominantly of a backbone of carbons linked by single bonds, with only hydrogen atoms attached. However, they may also contain doubly or R Function triply bonded carbons, as well as other elements. These atoms or groups of atoms 2-4tend to FUNCTIONAL GROUPS: CENTERS OF REACTIVITY be sites of comparatively high chemical reactivity and are referred to as functional groups or functionalities. Such groups have characteristic properties, and they control the reactiv- Many organic Carbonmolecules frame consist predominantlyFunctional of a backbone of carbons linked by single R Function ity of the molecule as a whole. bonds, with onlyprovides hydrogen atomsgroup attached. imparts However, they may also contain doubly or triply bonded carbons,structure as well as otherreactivity elements. These atoms or groups of atoms tend to Hydrocarbons are molecules that contain only be sites of comparatively high chemical reactivity and are referred to as functional groups or functionalities. Such groups have characteristic properties, and they control the reactiv- hydrogen and carbon Carbon frame Functional ity of the molecule as a whole. We begin our study with hydrocarbons, which have the general empirical formula CxHy. provides group imparts Those containing only single bonds, such as methane, ethane, and propane, are called structure reactivity alkanes. Molecules such as cyclohexane, whose carbons form a ring, are called cycloalkanes.Hydrocarbons are molecules that contain only Alkanes lack functional groups; as a result, they are relatively nonpolar and Moleculesunreactive.hydrogen The such andas cyclohexane, carbon whose carbons form a ring, are called cycloalkanes. properties and chemistry of the alkanes are described in this chapter and in ChaptersWe 3 andbegin 4. our study with hydrocarbons, which have the general empirical formula CxHy. Those containing only Cycloalkanessingle bonds, such as methane, ethane, and propane, are called Alkanes alkanes. Molecules such as cyclohexane, whose carbons form a ring, are called cycloalkanes. H2 CH4 CH3OOCH3 CH3 CH2OCH3 CH3OCH2OCH2OCHAlkanes3 lack functional groups;C as a result, they are relatively nonpolar and unreactive. The Methane Ethane Propane Butane properties and chemistry of the alkanes are described in this chapter and in Chapters 3 and 4. H2C CH2 Cycloalkanes Double and triple bonds are the functional groups of alkenes and alkynes, respectively. H2C CH2 Alkanes Their properties and chemistry are the topics of Chapters 11 through 13. Cyclopentane H2 CH4 CH3OOCH3 CH3 CH2OCH3 CH3OCH2OCH2OCH3 C Methane Ethane Propane Butane Alkenes and Alkynes H2C CH2 H2 H C CH H DoubleDoubleand andtriple triplebonds bonds areare thetheC functionalfunctional groupsgroups of alkenesof alkenes and alkynes,and alkynes, respectively.respectively . 2 2 i Their properties and chemistry are the topics of Chapters 11 through 13. Cyclopentane CH2PCH2 CPCH2 HCq CH CH3OCqCH H2C CH2 f CH3 H C AlkenesCH and Alkynes 2 2 H Ethene Propene Ethyne Propyne CH 2 (Ethylene) (Acetylene) H2 C i H C CH CH2PCH2 CyclohexaneCPCH2 HCq CH CH3OCqCH 2 2 f A special hydrocarbon is benzene, C6H6, in which three double bonds are incorporated CH 3 H2C CH2 into a six-membered ring. Benzene and its derivatives are traditionally called aromatic, Ethene Propene Ethyne Propyne C because some substituted benzenes do have a strong fragrance. Aromatic compounds, also (Ethylene) (Acetylene) H2 called arenes, are discussed in Chapters 15, 16, 22, and 25. Cyclohexane 3 A special hydrocarbon is benzene, C6H6, in which three double bonds are incorporated Aromatic Compounds (Arenes) into a six-membered ring. Benzene and its derivatives are traditionally called aromatic, because some substituted benzenes do have a strong fragrance. Aromatic compounds, also H CH3 called arenes, are discussed in Chapters 15, 16, 22, and 25. HHC HHC C C C C Aromatic Compounds (Arenes) C C C C H CH3 H C H H C H HHC HHC H H C C C C Benzene Methylbenzene C C C C (Toluene) H C H H C H H H Benzene Methylbenzene (Toluene) 2-4 Functional Groups: Centers of Reactivity CHAPTER 2 69 by an acid dissociation constant Ka. Removal of a proton from an acid generates its conju- gate base; attachment of a proton to a base forms its conjugate acid. Lewis bases donate an electron pair to form a covalent bond with Lewis acids, a process depicted by a curved arrow pointing from the lone pair of the base toward the acid. Electrophiles and nucleo- philes are species in organic chemistry that interact very much like acids and bases. The carbon–halogen bond in the haloalkane is its functional group. It contains an electrophilic carbon atom, which reacts with nucleophiles